Mitigation of line and neutral current harmonics in three-phase distribution systems

This paper presents a novel technique for the mitigation of line and neutral current harmonics in three-phase distribution systems. The proposed system uses a three-phase, four wire, PWM bi-directional converter with battery storage. The converter is connected to the utility supply through link inductors. The line harmonic currents are reduced based on a principle that the current flows through the link inductor will contain purely fundamental frequency if the voltage across the inductor, is a pure sinewave. Beside its function as an active filter, the system can additionally function as a load voltage stabiliser, neutral current mitigator and reactive power compensator. Results from simulation using PSCAD/EMTDC and laboratory tests are presented in this paper